MIKC-Type MADS-Box Gene Family Discovery and Evolutionary Investigation in Rosaceae Plants

MADS-box is an important transcriptional regulatory element in plant growth. The MIKC-type MADS-box genes play important roles. However, the identification and evolutionary investigation of MIKC-type MADS-box family members in Rosaceae have been inadequate. Therefore, based on whole-genome data from Prunus dulcis, Prunus salicina, Prunus armeniaca, Prunus persica, Prunus mira, and Amygdalus nana, we depicted the evolution and divergence patterns of MIKC-type MADS-box family genes. In this study, we found 222 MIKC-type MADS-box genes from six Rosaceae species. These genes were classified into five clades, and only motif 1 was identified across all MIKC-type MADS-box proteins, except PdMADS42 and PmiMADS16. The structural properties of these genes significantly varied in sequence lengths between species, despite the high levels of similarity in exon lengths and numbers. MIKC-type MADS-box genes were found to have mostly been limited through purifying selection processes. Remarkably divergent regions were found inside the MIKC-type MADS-box genes' domains, where clade III displayed more conserved activities and may have retained more original functions over the evolutionary process; clade I, on the other hand, may have undergone substantial functional limitations in a specific functional role. These findings provide the groundwork for future research into the molecular evolutionary processes of the plant MIKC-type MADS-box gene family.